1. Field of the Invention
This invention relates to tumbling apparatus and, in particular, to improved vibrating tumbling machines for mixing materials and for cleaning or shake-out of parts to be processed, such as castings, moldings or bulk material with or without a working media.
2. The Problem and the Prior Art
It was found sometime ago that an improved finish could be obtained on cast or molded parts by adding a vibratory motion to the tumbling apparatus. In the early 1960's, I developed and patented under U.S. Pat. No. 3,157,004, an improved burnishing apparatus using a U-shaped tub mounted on trunnions. Vibratory force was applied directly to the U-shaped tub and passed through the center of gravity of the tub. When the tub was tilted about the trunnions, the vibratory force was used to discharge the media and parts from the tub.
Although improved burnishing of the parts resulted from the above use of vibratory motion through the center of gravity of the tumbling apparatus, problems continued with the balance of the machine, with the wear on bearings, and with the time it took to obtain the finish.